The folksy 62-year-old Bavarian club president, who also runs a flourishing sausage company, was arrested and bailed almost a year ago in a scandal that rocked German sport and politics.
He will face seven charges of evading €3.5 million in taxes, according to Munich daily Süddeutsche Zeitung, quoting from the still-secret prosecution case.
Hoeneß has stayed on so far as president of the European champions, amid expressions of loyalty from fans, players and corporate sponsors such as Adidas, Audi, VW and Deutsche Telekom.
But a conviction would likely spell the end of his illustrious football career and possibly a stint in jail, the usual punishment in Germany for tax evasion above €1 million.
Hoeneß has spent more than four decades with the Bavarian sporting giants – first as player, helping win then West Germany the 1974 World Cup, then as team manager and, since 2009, as club president.
Since the tax scandal broke, Hoeneß – long a TV chat show regular outspoken about his conservative political views – has admitted to having been a compulsive stock market "gambler".
He said he received a 20 million deutschmark (€10.2 million) loan "for gambling" in his Swiss bank account in 2001 from the late Robert Louis-Dreyfuss, then chief of club supplier and shareholder Adidas, the sportswear company.
"At times I was trading day and night with sums that are hard for me to comprehend today, sometimes the amounts were extreme," Hoeneß told German media about his online trading years, which he said came to an end when he took major losses from 2006 and then amid the global economic crisis.
In 2011 Berlin and Bern agreed on steps to tax Germans' wealth hidden in Swiss bank accounts by early 2013.
However the German opposition in late 2012 torpedoed a measure to allow anonymous settlements with one-off payments, arguing that these would unfairly grant criminal amnesty to tax dodgers.
Hoeneß has said he turned himself in to tax authorities on January 17th last year over an unspecified amount of unpaid taxes. At the time some German media were already reporting on the tax troubles of an unnamed football official.
Prosecutors are expected to argue that the self-reporting contained irregularities and is invalid because authorities already had Hoeneß in their crosshairs at the time.
On March 20th, police searched Hoeneß' lakeside villa, presented him with an arrest warrant but released him on five million euros' bail, in an operation that was only made public by a news magazine the following month.
Despite widespread criticism of Hoeneß — including from Chancellor Angela Merkel who voiced "disappointment" — his initial offer to resign in May was rejected by the supervisory board of the powerhouse club.
Charges were laid in July but not publicly released. Under German tax law, they remain secret until they are read out in court.
The trial is scheduled to last four days, with a verdict expected as early as Thursday.
The maximum punishment for major tax fraud is 10 years jail, but shorter terms which can be suspended are far more common.
Public interest in the case has been intense – the 49 allocated media spots to cover the trial were filled within 27 seconds, Munich's higher regional court said.
Hoeneß has said he will seek to convince the judge of his innocence.
"I am still of the opinion that my (tax) advisor's work was okay and the verdict must reflect that," he said in a December interview.
Early this year he told Bayern fans: "I don't want to make myself into some sort of a saint, everyone knows that I made a big mistake. But I don't think that I have become a bad person."